Impact of Network Deployment on the Performance of NCR-assisted Networks

TL;DR

The paper tackles mmWave 5G coverage challenges under backhaul constraints by introducing network-controlled repeaters (NCRs) and a system-level model to evaluate their performance. It formalizes the NCR architecture (NCR-MT and NCR-Fwd) and derives a SINR framework where the received useful power $S_{u_x,k}$, interference $I_{u_x,k}$, and noise $N_{u_x,k}$ combine through $\rho_{u_x,k} = \dfrac{S_{u_x,k}}{I_{u_x,k} + N_{u_x,k}}$, while treating NCRs as network-managed, UE-transparent elements with beamformed links. The study analyzes five deployment scenarios (benchmark plus four NCR configurations) in a Madrid-grid urban setting, showing that properly planned NCRs can notably boost SINR, especially for edge and uplink users, with two NCRs at the central-block corners delivering a favorable balance across the network. The findings underscore the importance of deployment planning and suggest that NCR-assisted densification can enable faster, fiber-free backhaul deployment while yielding practical gains, albeit with cost considerations for real-world implementation.

Abstract

To address the need of coverage enhancement in the fifth generation (5G) of wireless cellular telecommunications, while taking into account possible bottlenecks related to deploying fiber based backhaul (e.g., required cost and time), the 3rd generation partnership project (3GPP) proposed in Release 18 the concept of network-controlled repeaters (NCRs). NCRs enhance previous radio frequency (RF) repeaters by exploring beamforming transmissions controlled by the network through side control information. In this context, this paper introduces the concept of NCR. Furthermore, we present a system level model that allows the performance evaluation of an NCR-assisted network. Finally, we evaluate the network deployment impact on the performance of NCR-assisted networks. As we show, with proper network planning, NCRs can boost the signal to interference-plus-noise ratio (SINR) of the user equipments (UEs) in a poor coverage of a macro base station. Furthermore, celledge UEs and uplink (UL) communications are the ones that benefit the most from the presence of NCRs.

Figures (6)

• Figure 1: Benchmark scenario with a crowded street on the top and a macro gNB in the middle bottom block.
• Figure 2: NCR links.
• Figure 3: Links considered in the SINR estimation.
• Figure 4: Evaluated scenarios.
• Figure 5: CDF of SINR in downlink.